Hello, one of the very few hangups I have with DO, is that when previewing a file to see what it is - picture music or video, when I go to move it or delete it, the file is locked because its being previewed. This seems oddly flawed and I'm sure is a windows thing behind the scenes.
Couldn't a command or drag to move/delete/etc. First unlock the file and ditch preview? Seems like an easy fix somewhere.
Also, have you found an updated media extension for playing more file types?
If the deletion is done in Opus then it should ask the viewer pane (but not the standalone viewer, if that's in use) to close the file first.
Pictures (at least any common formats) shouldn't be locked in the viewer, since Opus handles those itself and doesn't keep the files locked after loading the images inside them.
Movies might, depending on the viewer components involved.
PDFs and other documents may as well. They shouldn't, according to the Preview Handler API specifications, but a lot of preview handlers (including the MS Office ones and most PDF viewers like Adobe Reader) break those rules. We provide a workaround for those via an option to open temporary copies of them instead of the real files. (That option wouldn't work well with videos, though, since they tend to be large and take too long to copy.)